1. Field of the Invention
The present invention relates to a structure of an engine. More particularly, the present invention relates to a structure of a gasoline direct injection engine having improved operational performance.
2. Description of Related Art
In general, a GDI (gasoline direct injection) technology has been developed to improve fuel efficiency and performance of an internal combustion engine. The GDI engine technology is to directly inject fuel into the combustion chamber, not into the intake pipe.
Since it is possible to directly inject fuel into the combustion chamber and produce a fuel-air mixture layer by using the GDI engine, it is possible to produce a condensed mixture by concentrate air and fuel around a spark plug. Accordingly, the engine can operate at a very small air/fuel ratio and wall wetting is reduced in comparison to injecting fuel to the intake port in the related art, such that it is possible to accurately control the amount of fuel and improve fuel efficiency and performance, and accordingly, the GDI engines are recently increasingly used.
Various methods of mixing air with fuel well and maximally concentrating an air-fuel mixture around the spark plug has been proposed to smoothly operate the engine at a small air/fuel ratio.
A vortex is generated in the axis perpendicular to the movement direction of the piston or with respect to the movement direction axis of the piston in the internal combustion engine, in which the former one is called ‘tumble’ and the later one is called ‘swirl’.
Since the mixing ratio and concentration of the air and fuel depend on the flow level of the tumble and the swirl, design should be performed in consideration of the tumble and swirl to improve the operational performance of the GDI engine.
The tumble and swirl particularly depends on the shape of the top of the piston, the design of the top of the piston should be improved to improve the operational performance of the GDI engine.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.